48 research outputs found

    Mineral Potential of Arctic Canada

    Get PDF
    Canada is on the threshold of a major new phase in the development of its Arctic resources. The Prudhoe Bay discovery triggered a boom in northern petroleum exploration that is just getting into high gear this year. Mining activity also has greatly expanded in the last few years with some 73 active exploration programs underway and several large new mines just coming into production. The size of these ventures is indicated by ore reserves of two lead-zinc mines to the value of 900 million dollars at Pine Point in southern Northwest Territories, and 1.2 billion dollars at the Anvil property in the southern Yukon Territory. Other properties with very large reserves are currently under development. Approximately 465,000 sq. miles of the 1.5 million square miles of Canada north of the 60th parallel are underlain by sedimentary rocks. A volumetric estimate of petroleum potential on the basis of rather scanty evidence is made at 54 billion barrels. With the current activity in the area it should be possible to improve this estimate considerably in the next 2 or 3 years. The two most promising areas are the Arctic Coastal Plains containing large volumes of young sedimentary rock and large structures, and the Mesozoic Sverdrup Basin also with many potential hydrocarbon traps. The Interior Plains of the mainland and the Arctic lowlands, as well as the fold belts of the Franklinian miogeosyncline indicate lesser potential

    Discovery of a Novel Activator of KCNQ1-KCNE1 K+ Channel Complexes

    Get PDF
    KCNQ1 voltage-gated K+ channels (Kv7.1) associate with the family of five KCNE peptides to form complexes with diverse gating properties and pharmacological sensitivities. The varied gating properties of the different KCNQ1-KCNE complexes enables the same K+ channel to function in both excitable and non excitable tissues. Small molecule activators would be valuable tools for dissecting the gating mechanisms of KCNQ1-KCNE complexes; however, there are very few known activators of KCNQ1 channels and most are ineffective on the physiologically relevant KCNQ1-KCNE complexes. Here we show that a simple boronic acid, phenylboronic acid (PBA), activates KCNQ1/KCNE1 complexes co-expressed in Xenopus oocytes at millimolar concentrations. PBA shifts the voltage sensitivity of KCNQ1 channel complexes to favor the open state at negative potentials. Analysis of different-sized charge carriers revealed that PBA also targets the permeation pathway of KCNQ1 channels. Activation by the boronic acid moiety has some specificity for the Kv7 family members (KCNQ1, KCNQ2/3, and KCNQ4) since PBA does not activate Shaker or hERG channels. Furthermore, the commercial availability of numerous PBA derivatives provides a large class of compounds to investigate the gating mechanisms of KCNQ1-KCNE complexes

    The macrophage in HIV-1 infection: From activation to deactivation?

    Get PDF
    Macrophages play a crucial role in innate and adaptative immunity in response to microorganisms and are an important cellular target during HIV-1 infection. Recently, the heterogeneity of the macrophage population has been highlighted. Classically activated or type 1 macrophages (M1) induced in particular by IFN-γ display a pro-inflammatory profile. The alternatively activated or type 2 macrophages (M2) induced by Th-2 cytokines, such as IL-4 and IL-13 express anti-inflammatory and tissue repair properties. Finally IL-10 has been described as the prototypic cytokine involved in the deactivation of macrophages (dM). Since the capacity of macrophages to support productive HIV-1 infection is known to be modulated by cytokines, this review shows how modulation of macrophage activation by cytokines impacts the capacity to support productive HIV-1 infection. Based on the activation status of macrophages we propose a model starting with M1 classically activated macrophages with accelerated formation of viral reservoirs in a context of Th1 and proinflammatory cytokines. Then IL-4/IL-13 alternatively activated M2 macrophages will enter into the game that will stop the expansion of the HIV-1 reservoir. Finally IL-10 deactivation of macrophages will lead to immune failure observed at the very late stages of the HIV-1 disease

    Proteomic Modeling for HIV-1 Infected Microglia-Astrocyte Crosstalk

    Get PDF
    Background: HIV-1-infected and immune competent brain mononuclear phagocytes (MP; macrophages and microglia) secrete cellular and viral toxins that affect neuronal damage during advanced disease. In contrast, astrocytes can affect disease by modulating the nervous system’s microenvironment. Interestingly, little is known how astrocytes communicate with MP to influence disease. Methods and Findings: MP-astrocyte crosstalk was investigated by a proteomic platform analysis using vesicular stomatitis virus pseudotyped HIV infected murine microglia. The microglial-astrocyte dialogue was significant and affected microglial cytoskeleton by modulation of cell death and migratory pathways. These were mediated, in part, through F-actin polymerization and filament formation. Astrocyte secretions attenuated HIV-1 infected microglia neurotoxicity and viral growth linked to the regulation of reactive oxygen species. Conclusions: These observations provide unique insights into glial crosstalk during disease by supporting astrocytemediated regulation of microglial function and its influence on the onset and progression of neuroAIDS. The results open new insights into previously undisclosed pathogenic mechanisms and open the potential for biomarker discovery an

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

    Get PDF
    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    Quality of transition to end-of-life care for cancer patients in the intensive care unit

    Get PDF
    Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.BACKGROUND: There have been few studies that have evaluated the quality of end-of-life care (EOLC) for cancer patients in the ICU. The aim of this study was to explore the quality of transition to EOLC for cancer patients in ICU. METHODS: The study was undertaken on medical patients admitted to a specialist cancer hospital ICU over 6 months. Quantitative and qualitative methods were used to explore quality of transition to EOLC using documentary evidence. Clinical parameters on ICU admission were reviewed to determine if they could be used to identify patients who were likely to transition to EOLC during their ICU stay. RESULTS: Of 85 patients, 44.7% transitioned to EOLC during their ICU stay. Qualitative and quantitative analysis of the patients' records demonstrated that there was collaborative decision-making between teams, patients and families during transition to EOLC. However, 51.4 and 40.5% of patients were too unwell to discuss transition to EOLC and DNACPR respectively. In the EOLC cohort, 76.3% died in ICU, but preferred place of death known in only 10%. Age, APACHE II score, and organ support, but not cancer diagnosis, were identified as associated with transition to EOLC (p = 0.017, p < 0.0001 and p = 0.001). CONCLUSIONS: Advanced EOLC planning in patients with progressive disease prior to acute deterioration is warranted to enable patients' wishes to be fulfilled and ceiling of treatments agreed. Better documentation and development of validated tools to measure the quality EOLC transition on the ICU are needed.Peer reviewe

    Structure, Function, and Modification of the Voltage Sensor in Voltage-Gated Ion Channels

    Full text link
    corecore